Komatsu PC88MR-10 Shop Manual page 982

40 Troubleshooting
Troubleshooting of hydraulic and mechanical system (H-
mode)
No. Cause
Malfunction of unload
7
valve
Malfunction of R.H.
travel control valve
8
(spool)
Malfunction of L.H.
travel control valve
9
(spool)
Defective center swivel
10
joint
11 Defective travel motor
12 Defective final drive
Defective adjustment of
travel deviation
13
adjustment plug
40-494
Procedure, measuring location, criteria, and remarks
Take care not to let foreign matter enter valve when re-installing spool.
a Be ready with engine stopped, then perform troubleshooting with engine at
high idle.
Unload pressure
a Release remaining pressure from hydraulic tank and piping, and then
perform troubleshooting with engine stopped.
Check for stuck or seized travel spool in control valve body.
(Spool must move smoothly and must not be caught.)
Remove travel spool from valve body and check it for defects and dirt.
Take care not to let foreign matter enter valve when re-installing spool.
a Release remaining pressure from hydraulic tank and piping, and then
perform troubleshooting with engine stopped.
Check for stuck or seized travel spool in control valve body.
(Spool must move smoothly and must not be caught.)
Remove travel spool from valve body and check it for defects and dirt.
Connect hoses from L.H. and R.H. travel motors to swivel joint changing
connecting ports with each other, and check whether direction in which
machine deviates changes.
The travel motor may have a defect in it. Check it.
(It may be checked whether or not the direction of travel deviation changes by
swapping right and left travel motor and final drive assemblies.)
a Check for unusual noise, unusual heat, and metallic powders in drained oil
to make judgment.
Adjust travel deviation adjustment plug. For details, see Testing and adjusting,
"Testing and adjusting travel deviation".
All control levers in NEUTRAL
3.4 ± 1.0 MPa
{35 ± 10 kg/cm 2 }
PC88MR-10